We are in the process of improving our method of measurement of the specific intracellular binding of dihydrotestosterone and we are developing an assay for the measurement of 5 alpha-reductase and 17-ketosteroid reductase activity. With this tool we will determine the characteristics of human skin fibroblast in normal and pathological conditions. We particularly plan to extend our work on the study of patients with androgen insensitivity as well as patients with other specific enzymatic defect in their biosynthesis of testicular androgens. In relation with these various in vitro studies of skin fibroblasts we are carrying out a number of investigations in vivo in patients with various abnormalities of sexual differentiation. Another aspect of this work will include the measurement of the specific intracellular binding of androgens in fibroblasts arising from various fetal organs. We plan to continue studies of the treatment of patients with Congenital Adrenal Hyperplasia. We are in the process of studying the response of the plasma levels of 17-hydroxyprogesterone, androstenedione throughout a 24 hour period using various types of therapy. This approach could be helpful as far as determining the mini um dose which might bringg about suppression of the adrenal cortex. We are continuing our study of the effect of malnutrition on various endocrine parameters. We are particularly involved in the area of cortisol metabolism in malnourished children as compared with normal subjects.